# Data Quality Issues Analysis Based on the evidence gathered, I've identified several data quality issues: ## 1. **Duplicate Records (Confirmed)** **Issue:** The 1992 Olympics contains systematic duplicate records. **Evidence from step-15:** - **Men's doubles, Gold (China)**: 2 records, 1 unique medalist, 1 country - **Men's doubles, Silver (Germany)**: 2 records, 1 unique medalist, 1 country - **Men's doubles, Bronze (South Korea)**: 2 records, 2 unique medalists, 1 country - **Women's singles, Gold (China)**: 2 records, 1 unique medalist, 1 country - **Women's singles, Silver (China)**: 2 records, 1 unique medalist, 1 country - **Women's singles, Bronze**: 2 records, 2 unique medalists, 2 countries **Impact:** 1992 shows 18 medals (step-1) when it should show 12 like most other years. This represents 6 duplicate records inflating the count by 50%. ## 2. **Inconsistent Medal Distribution Across Years** **Issue:** Medal counts vary unexpectedly across years. **Evidence from step-1 and step-4:** - **1988-2016** (except 1992): 12 medals per year, 4 events each - **1992**: 18 medals (due to duplicates), 4 events - **2020 & 2024**: 15 medals, 5 events each The jump from 12 to 15 medals in 2020-2024 appears legitimate (5 events vs 4), but 1992's 18 medals is anomalous. ## 3. **Event Distribution Anomalies** **Issue:** Uneven distribution of medals across event types. **Evidence from step-10:** - **Men's singles**: 30 medals - **Men's team**: 30 medals - **Men's doubles**: 18 medals - **Women's singles**: 18 medals - **Women's doubles**: 6 medals (significantly lower) - **Women's team**: 15 medals - **Mixed doubles**: 15 medals Women's doubles has only 6 medals across all years, suggesting either late introduction or data gaps. ## 4. **What is NOT a Problem (Confirmed Clean)** - ✓ **No null values**: 0 nulls across all key fields (step-0) - ✓ **Medal values consistent**: All values are 1 (Bronze), 2 (Silver), or 3 (Gold) with min=1, max=3 (step-1, step-2) - ✓ **Balanced medal types**: Exactly 44 of each medal type (step-2, step-9) - ✓ **Valid Olympic years**: All years divisible by 4 (step-5) - ✓ **No whitespace issues**: 0 rows with leading/trailing spaces or double spaces (step-12) - ✓ **Consistent country name lengths**: Each country has consistent min/max name length (step-11) ## Summary **Primary Issue:** Duplicate records in 1992 data (6 extra records) **Secondary Issue:** Uneven event representation (Women's doubles underrepresented) **Data Integrity:** Otherwise clean - no nulls, impossible values, or format inconsistencies detected